Well that sounds like a frustrating problem. I am no expert on these things for sure, but your post did trigger a thought about something I read recently. A virus called js.iestart.gen. It changes your IE start page, by altering your registry.
Here's a link to th Mcaffee info page.

http://vil.nai.com/vil/content/v_99066.htm

This little diddy tried to get me a couple of times, but my virus program nabbed it in time. Both times it had lodged itself in my temporary internet files. It came from just browsing.

Good Luck

Dragonseye